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// This file is part of par2cmdline (a PAR 2.0 compatible file verification and
// repair tool). See http://parchive.sourceforge.net for details of PAR 2.0.
//
// Copyright (c) 2003 Peter Brian Clements
//
// par2cmdline is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
//
// par2cmdline is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
#include "par2cmdline.h"
#ifdef _MSC_VER
#ifdef _DEBUG
#undef THIS_FILE
static char THIS_FILE[]=__FILE__;
#define new DEBUG_NEW
#endif
#endif
RecoveryPacket::RecoveryPacket(void)
{
diskfile = NULL;
offset = 0;
packetcontext = NULL;
}
RecoveryPacket::~RecoveryPacket(void)
{
delete packetcontext;
}
// Create a recovery packet.
// The packet header can be almost completely filled in using the supplied
// information and computation of the hash of the packet started immediately.
// The hash will be updated as new data is written to the packet.
void RecoveryPacket::Create(DiskFile *_diskfile,
u64 _offset,
u64 _blocksize,
u32 _exponent,
const MD5Hash &_setid)
{
diskfile = _diskfile;
offset = _offset;
// Record everything we know in the packet.
packet.header.magic = packet_magic;
packet.header.length = sizeof(packet) + _blocksize;
//packet.header.hash; // Not known yet.
packet.header.setid = _setid;
packet.header.type = recoveryblockpacket_type;
packet.exponent = _exponent;
// Start computation of the packet hash
packetcontext = new MD5Context;
packetcontext->Update(&packet.header.setid,
sizeof(RECOVERYBLOCKPACKET)-offsetof(RECOVERYBLOCKPACKET, header.setid));
// Set the data block to immediatly follow the header on disk
datablock.SetLocation(_diskfile, _offset + sizeof(packet));
datablock.SetLength(_blocksize);
}
// Write data from the buffer to the data block on disk
bool RecoveryPacket::WriteData(u64 position,
size_t size,
const void *buffer)
{
// Update the packet hash
packetcontext->Update(buffer, size);
// Write the data to the data block
size_t wrote;
return datablock.WriteData(position, size, buffer, wrote);
}
// Write the header of the packet to disk
bool RecoveryPacket::WriteHeader(void)
{
// Finish computing the packet hash
packetcontext->Final(packet.header.hash);
// Write the header to disk
return diskfile->Write(offset, &packet, sizeof(packet));
}
// Load the recovery packet from disk.
//
// The header of the packet will already have been read from disk. The only
// thing that actually needs to be read is the exponent value.
// The recovery data is not read from disk at this point. Its location
// is recovered in the DataBlock object.
bool RecoveryPacket::Load(DiskFile *_diskfile,
u64 _offset,
PACKET_HEADER &_header)
{
diskfile = _diskfile;
offset = _offset;
// Is the packet actually large enough
if (_header.length <= sizeof(packet))
{
return false;
}
// Save the fixed header
packet.header = _header;
// Set the data block to immediatly follow the header on disk
datablock.SetLocation(diskfile, offset + sizeof(packet));
datablock.SetLength(packet.header.length - sizeof(packet));
// Read the rest of the packet header
return diskfile->Read(offset + sizeof(packet.header), &packet.exponent, sizeof(packet)-sizeof(packet.header));
}
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